> ## Documentation Index
> Fetch the complete documentation index at: https://ownpay.org/docs/llms.txt
> Use this file to discover all available pages before exploring further.
> ## Agent Instructions
> OwnPay is licensed under AGPL-3.0 and is completely free - no licensing fees.
> Production docs URL: https://ownpay.org/docs - append .md to any page URL for clean markdown.
> OwnPay requires PHP 8.3+, MySQL/MariaDB, and Redis.
> MCP server available at https://ownpay.org/docs/mcp for programmatic documentation queries.
> Use root-relative links (e.g. /quickstart) for internal navigation - do NOT include /docs prefix.
> Plugin development: consult /developer/plugins/ pages for correct interfaces and manifests.
> Canonical locations: API auth = /api/authentication, webhook verification = /api/webhooks, rate limits = /resources/rate-limiting, transaction statuses = /fundamentals/payment-flow.
> The documentation uses the Diataxis framework: Tutorials (learning), How-to (tasks), Reference (lookup), Explanation (understanding).
# Plugin System - Extensible Architecture
> OwnPay's plugin architecture supports four types - gateway, addon, theme, and integration - using a manifest-based discovery system with hooks, filters, and a capabilities model.
This documentation is for OwnPay v0.2.0-beta, a open-source, self-hosted PHP 8.3 payment gateway with multi-brand support, 100+ payment gateways, and double-entry ledger. It is licensed under AGPL-3.0 with zero transaction fees. The docs URL is [https://ownpay.org/docs](https://ownpay.org/docs). API base URL is `https://your-domain.com/api/v1` with Bearer token authentication. Amounts are bcmath strings. The platform supports 4 plugin types: gateway, addon, theme, and integration. Canonical locations: API auth = /api/authentication, webhook verification = /api/webhooks, rate limits = /resources/rate-limiting, transaction statuses = /fundamentals/payment-flow. The documentation follows the Diataxis framework (Tutorial, How-to, Reference, Explanation).
OwnPay's core handles routing, the ledger, brands, and the checkout framework. Everything else - payment providers, custom themes, extra features, and third-party integrations - is delivered through **plugins**. This means you can extend OwnPay without modifying a single line of core code.
## Four plugin types
Add a new payment provider. Each gateway plugin implements the payment adapter contract: process payments, handle callbacks, manage refunds, and declare supported currencies. Examples: Stripe, bKash, Razorpay.
Add features to the admin panel or checkout. Addons can register admin pages, API endpoints, scheduled jobs, and UI components. Examples: subscription management, CRM sync, advanced reporting.
Customize the checkout experience. Theme plugins provide Twig templates, CSS, JavaScript, and asset files that override the default checkout appearance per brand.
Connect OwnPay to external platforms. Integration plugins handle OAuth flows, data syncing, and webhook translation for WooCommerce, WHMCS, Laravel, and other frameworks.
## Manifest-based discovery
Every plugin lives in the `modules/` directory and declares itself through a `manifest.json` file. OwnPay's plugin loader scans this directory at boot time, reads each manifest, validates the structure, and registers the plugin with the PSR-4 autoloader.
```json theme={"theme":{"light":"github-light","dark":"github-dark"}}
{
"slug": "stripe",
"name": "Stripe Payment Gateway",
"version": "1.0.0",
"type": "gateway",
"entrypoint": "src/StripeGateway.php",
"namespace": "OwnPay\\Gateways\\Stripe"
}
```
## Hook system
Plugins interact with OwnPay and with each other through two mechanisms:
**Filters** modify data before an action runs:
```php theme={"theme":{"light":"github-light","dark":"github-dark"}}
// A plugin adjusts the payment amount
$amount = Hook::apply('payment.amount', $amount, $payment);
```
**Actions** react to events after they occur:
```php theme={"theme":{"light":"github-light","dark":"github-dark"}}
// A plugin sends a Slack notification after payment completes
Hook::do('payment.completed', $payment);
```
OwnPay exposes over 60 hooks across categories like `payment.*`, `customer.*`, `gateway.*`, `webhook.*`, and `system.*`.
## Capabilities system
Plugins declare what they need through a **capabilities** array in their manifest. OwnPay checks these capabilities before loading the plugin. This lets the system warn administrators about missing dependencies before activation.
Common capabilities: `payment_processing`, `admin_ui`, `cron_jobs`, `webhook_handler`, `api_endpoints`.
## Plugin sandbox
OwnPay restricts plugin upload to the platform owner (master administrator). A **footgun scanner** runs on upload and blocks dangerous functions like `eval()` and direct OS command execution. Standard PHP operations - reflection, callbacks, file I/O - are permitted.
The security boundary is **owner-only upload**, not in-process isolation. Plugins run with full application trust, similar to the WordPress plugin model. Only install plugins from sources you trust.
## Related pages
* [Plugin overview (developer)](/docs/developer/plugins/overview) - build and register your first plugin
* [Hooks reference](/docs/developer/plugins/hooks) - complete list of available filters and actions
* [Events reference](/docs/developer/plugins/events) - event categories and listener registration
* [Capabilities](/docs/developer/plugins/capabilities) - declare and check plugin capabilities
* [Build a gateway plugin](/docs/developer/plugin-types/gateway) - step-by-step gateway development guide
## Related topics
- [Plugin System](/docs/developer/plugins/overview.md)
- [How OwnPay Works](/docs/fundamentals/how-ownpay-works.md)
- [OwnPay Architecture: PHP Core, Middleware, and Plugins](/docs/resources/architecture.md)
- [OwnPay Skills for AI Agents - Platform Knowledge Pack](/docs/developer/ai/skills.md)
- [OwnPay: Self-Hosted Payment Orchestrator](/docs/introduction.md)